# CVE-2026-48685: Memory corruption in n/a

> FastNetMon Community Edition suffers from out-of-bounds memory access due to incorrect BGP attribute parsing, potentially allowing attackers to cause denial of service or execute arbitrary code.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 May 2026
- **Updated:** 26 May 2026
- **Also known as:** DEBIAN-CVE-2026-48685, GHSA-4h2g-xxvj-v3w5, UBUNTU-CVE-2026-48685

## What is CVE-2026-48685?

CVE-2026-48685 is a medium-severity memory corruption vulnerability in n/a, published on 26 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.

Weakness: CWE-130 (Improper Handling of Length Parameter Inconsistency)

## Which versions are affected by CVE-2026-48685?

It affects 1 product.


Products: Pavel-Odintsov Fastnetmon.

## How do I fix CVE-2026-48685?

Upgrade to a fixed version.

## Is CVE-2026-48685 being exploited?

There is no known exploitation of CVE-2026-48685 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-48686](https://insights.sbomify.com/CVE-2026-48686/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-48689](https://insights.sbomify.com/CVE-2026-48689/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-48687](https://insights.sbomify.com/CVE-2026-48687/): Command injection in n/a (high 8.1)
- [CVE-2026-48692](https://insights.sbomify.com/CVE-2026-48692/): Missing authorization in n/a (high 8.1)
- [CVE-2026-48694](https://insights.sbomify.com/CVE-2026-48694/): Command injection in n/a (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48685 and fix it if it is affected.

What it is: CVE-2026-48685 is a medium-severity memory corruption vulnerability in n/a, published on 26 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-48685 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48685/ (Markdown: https://insights.sbomify.com/CVE-2026-48685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48685
- OSV: https://osv.dev/vulnerability/CVE-2026-48685

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48685/
Summaries are generated and may contain mistakes; the official description above is the record.